Process of extracting zinc and copper from their ores.



desirable for general use.

UNITED STATES PATENT OFFICE.

CALEB G. COLLINS, OF NEW YORK, N. Y., ASSIGNOR TO CALVIN AMORY ISTEVENS, OF SAME PLACE.

PROCESS OF EXTRACTING ZINC AND COPPER FROM THEIR ORES SPECIFICATIONformingpart of Letters latent No. 659,340. dated October 9, 1900.

Application filed October 30,1899. Serial No. 735,291. (No specimens.)

which the invention appertains to make and use the same. My inventionrelates to the extraction of copper and zinc from their ores; and itconsists, essentially, in subjecting the reduced orcrushed ores of thesemetals to the action of a solution of What are technically known asniter-cake, a residuum resulting from the manufacture of nitric acid,and saltcake, a residuum resulting from the manufactureof muriatic acid,thus utilizing for this purpose What have been practically wasteby-products, which are comparatively cheap, plentiful, and easilyobtainable.

In using the term niter-cake I refer to a residual substance composedsubstantially as follows: sulfate of sodium, 75.80 per cent.; freesulfuric acid, 16.68 per cent.; Water, six per cent; insoluble matter,1.52 per cent; total, one hundred per cent.

In using the term salt-cake I refer to a residual substance composedsubstantially as follows: sulfates of sodium, ninety-five per cent;chlorid of sodium, two per cent; sulfuric acid, two per cent; magnesia,one per cent; total, one hundred per cent.

The strength of the solution may be varied with relation to thecharacter of the ore to be treated. I have found a saturated solutionShould the ore carry iron, alumina, or other soluble substances in largequantities, a weaker solution may be used to avoid waste by reason ofthe affinity of the solution for such substances, its affinity forcopper and zinc being greater, so that in the absence of an excess ofthe niter-cake and salt-cake in the solution the latter will take uponly the copper or zinc. For instance, I have found when using a weak'solut-i0nsay about 5 Baum scalethat the solution exercises a selectiveaction on these metals.

The process consists in immersing the zinc and copper ore, roasted orotherwise, in a powdered state in a bath of Water in Which more or lessof the niter-cake and salt-cake are held in solution and in subjectingthe powdered ore to the action of this solution until all the copper orzinc present is dissolved out and extracted from the ore. The bath isthen filtered to remove the residual ore and thecopper 0r zincelectrically deposited from thesolution or otherwise precipitated, asmay be preferred.

I am aware that it has been proposed to reduce gold ore by calcinationwith sodic sulfate or salt-cake, as in patent to C. P. Williams, No.292,605, of January 29, 1884; also, that it has been proposed to useniter-cake and salt-cake for preparing gold ore for amalgamation anddesulfurization, as inpatents to C. R. Squire, No. 309,168, of December9, 1884, and Nos. 312,586 and 312,587, of February 17,1885; but I am notaware that powdered zinc or copper ores, either roasted or raw, haveever been treated to a solution of niter-cake and salt-cake for thepurpose of dissolving out the said metals, as above described.

What I claim as my invention, and desire to secure by Letters Patent, is

Theherein-described process of treating ores of copper and zinc, andother metals soluble in a strong solution of the solvent employed, whichconsists in exposing the con]- minuted ore to the action of a solutionof sodium sulfate containing sodium bisulfate, sodium chlorid andhydrochloric acid (salt cake and niter-cake solution) in proportion tothe contained copper and zinc but sufficient in strength to dissolveonly copper and zinc therefrom, and subsequently recovering these metalsfrom the solution, substantially as described.

CALEB G. COLLINS.

WVitnesses:

D. W. GARDNER, GEO. WM. MIATT.

